1. Field of the Invention
The present invention is directed to a sewing machine, and in particular, to a unitary double-acting piston chain thread cutter assembly for a sewing machine.
2. Description of Related Art
Sewing machines are used to produce a multitude of garments at a high speed of production. Chain threads between garments must be cut quickly, and preferably, without stopping the production of the next garment.
Chain thread cutter assemblies are widely used for cutting the chain thread formation between garments or pieces. By way of example, Clinton Industries manufactures a cutter assembly (model 3115FCA) that is permanently mounted via screws drilled into the top plate of the sewing machine. The cutter assembly comprises two separate sections: a driver section and a body section. To install the cutter assembly holes must first be drilled in the top plate of the sewing machine. Then the body section is secured to the top plate of the sewing machine behind the presser foot via screws. The driver section is placed behind the body section and slid together so that projection members extending from the driver section are received in complementary shaped apertures defined in the body section. A guard is positioned so that it extends over the top surface of both sections and secured via a screw to the driver section. Because of the separate components, assembly of the cutter assembly is time consuming and requires proper alignment of the two sections so that the guard fits over the top. Another disadvantage of this conventional device is that it is permanently affixed to the top plate of the sewing machine and thus can not be readily removed. The driver section includes a driving piston. During installation the driver section is arranged in the lateral direction so that the driving piston is substantially perpendicular to the direction of the cutter assembly. This is disadvantageous in that it is difficult to mount the assembly on space restricted overedge machines.
It is therefore desirable to provide a unitary chain thread cutter assembly that may be readily and releasably mounted to a wide variety of sewing machines.